In portable battery operated products such as a wireless selective call capable device, many attempts have been made to design circuits that effectively control and distribute power to functional circuits within the device. Prior art systems have used both capacitive and inductive topology voltage multipliers for generating voltages necessary to power such devices as microcomputers, information displays, linear support circuits for power distribution and management, as well as signal processors. However, a persistent problem has been that the efficiency of such voltage multipliers is typically low, thus resulting in an unnecessary loss of power when used to supply said devices.
Thus, what is needed is an efficient apparatus that not only generates the necessary voltage supplies, but also intelligently selects the most efficient voltage supply available for powering such devices.